What is the Type of Breast Cancer Classified As HER2/neu?

Orange County, California surgeon Gregory T. Ginsburg, MD, FACS, defines HER2/neu as an “oncogene,” which is basically a tumor marker, “so when you take out a specimen of breast cancer tissue, they test it for various prognostic indicators,” Dr. Ginsburg tells SurvivorNet.

“When they study a tissue sample from a breast cancer biopsy or surgery, this is one of the things they check for,” Dr. Ginsburg explains. “If it is present, they characterize it as so and also quantitate it. Negative is better for a person's prognosis.”

HER2/neu and HER2 are essentially interchangeable terms. They do not represent two different proteins/receptors.

Learning More About HER2

HER2, or human epidermal growth factor 2, is a protein present on breast cancer cells. The amount of this protein can be used to classify breast cancer into different subtypes, such as HER2 positive for those cancers which have an abundance of the protein. HER2-negative breast cancers have low-to-no levels of the HER2 protein.

“When they study a tissue sample from a breast cancer biopsy or surgery, this is one of the things they check for. If it is present, they characterize it as so and also quantitate it. Negative is better for a person's prognosis,” says Dr. Ginsburg, noting that “HER2/neu,” while not an overly familiar term, has been used in medical literature for a long time.

In light of Katie Couric’s cancer news and HER2/neu diagnosis, we wanted to use this opportunity to educate people further on the topic.

According to the NCI, HER2/neu is a protein involved in normal cell growth. HER2/neu “may be made in larger than normal amounts by some types of cancer cells,” including breast in this case, but also bladder, ovarian, stomach, and pancreatic cancers.

“This may cause cancer cells to grow more quickly and spread to other parts of the body. Checking the amount of HER2/neu on some types of cancer cells may help plan treatment.”

Traditionally, the presence of HER2 has been divided into two groups (positive or negative). But that leaves around 50% percent of patients somewhere in the middle. Some of these patients can be classified as HER2 "low" (some HER2 negative patients can show minimal expression).

Separate from HER2negative classification is the presence or absence of hormone receptors on the surface of cancer. The two types are:

• Hormone receptor-positive (HR-positive) breast cancer: When the cells use estrogen, progesterone, or both to grow and replicate.
• Triple-negative breast cancer: When the hormone receptors are absent. Triple-negative cancers do not have the 2 hormone receptors, nor the HER2 protein, hence triple-negativity.

Learning More About HER2/neu

The medical world is always rapidly changing, especially in recent years. Therefore it is essential for doctors to stay up on all of the breakthrough tests and treatments to help better inform their patients.

“We need to make sure that we have the support systems for oncologists to be able to know what the most cutting edge cancer treatments are for the patients that they’re treating,” Dr. Craig Bunnell, chief medical officer at the Dana Farber Cancer Institute, says to SurvivorNet.

On the topic of HER2/neu, Dr. Bunnell says: “We need a broad education for all people who have been diagnosed with breast cancer to know whether they had any HER2 positivity in their tumors.”

Furthermore, according to Dr. Bunnell, doctors need to know whether their patients are estrogen receptor-positive or not, which is very similar.

Additionally, if you have metastatic breast cancer, did it test positive at all for HER2/neu? And is there a therapy available for me?” he adds, stressing the questions that need to be answered when it comes to a thorough diagnosis and treatment plan.

Do You Have HER2-Positive Metastatic Breast Cancer? Here's A Breakdown Of Some Of Your Treatment Options

An Important Test for HER2 Patients

The good news is we now have a way to determine how high risk you are for your cancer returning with HER2, and whether or not you even need chemotherapy treatment, which up until this test, was given as standard treatment for safety, or “just in case.”

The Oncotype DX test is a genetic test that profiles the tumors of women who have early-stage hormone receptor-positive, HER2 negative breast cancer (or people with DCIS–ductal carcinoma in situ). The test can help predict the risk of your breast cancer returning.

After surgery, a piece of the tumor is sent off to be tested. According to Memorial Sloan Kettering’s website, “a group of 21 genes in this tissue are analyzed to help determine prognosis (how likely your breast cancer is to return) and if getting chemotherapy will improve your chances that the cancer will not come back.”

The result is a number otherwise known as the "Oncotype DX score."

The score determines if a woman is at low, intermediate, or high risk of recurrence and based on that result, whether a woman may benefit from the addition of chemotherapy before receiving hormonal therapy. In general, women who have a low score do not need chemotherapy. Women who have a high score may decrease the risk of the cancer coming back with the addition of chemotherapy.

What is the Oncotype DX Test and Do I Need it?

For women with an intermediate score, one of the largest breast cancer studies ever done recently reported that women over the age of 50 with a score less than 25 did not benefit from chemotherapy. In general, those women have an excellent prognosis with hormone therapy alone. For women younger than 50, and scores greater than 15, they may still benefit from chemotherapy prior to hormonal therapy.

Medical professionals in cancer care have been calling this one of the biggest development in 15 to 20 years. There seems to be something of a public health moment here right now, educating people to go and ask, “what’s my test number?”

“We need to make sure that patients are educated about these [numbers] as well, because frankly that’s beneficial for them and beneficial for their physicians … but we need to make sure that that information is out there and that we have ways to help oncologists who, you know, most patients are getting their cancer care [from],” Dr. Bunnell explains.

Katie Couric’s Recent HER2/neu Breast Cancer Announcement

Journalist Katie Couric, 65, recently announced that she was diagnosed with hormone receptor-positive HER2/neu-negative breast cancer. In Couric's case, it didn't change her treatment path, but for some women there could be a change in treatment based on the new category of "HER2/neu."

Couric said her course of treatment included radiation and medication specifically, something called an aromatase inhibitor, which is used to block the activity of the aromatase enzyme and, therefore, stop the production of estrogen. That, in turn, helps to slow down the growth of tumor cells that are sensitive to estrogen.

Related: 5 Critical Lessons From Katie Couric's Breast Cancer Announcement

When your doctor determines the treatment for you they have to consider many factors in the decision. Some questions may be: What is the size of the tumor, and are lymph nodes or other parts of the body involved? The biology of your tumor is also important: is your tumor positive for the HER2 receptor or hormone receptors? Did you inherit an increased risk for breast cancer and/or did your lifestyle increase your risk?

Couric said she took the above-mentioned oncotype test and it was a low score meaning she wouldn't need chemotherapy, a common drug treatment for cancer. Previous to this test a lot of women would have continued to get chemotherapy, which just goes to show how monumental this test is and what it means for patients who want to avoid longterm side effects from treatment, if they are able.

Contributing by SurvivorNet staff.

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